caa a22 4500 388022043 CHVBK 20180307124927.0 cr unu---uuuuu 161130e199807 xx s 000 0 eng 10.1557/JMR.1998.0268 doi S0884291400045040 pii (NATIONALLICENCE)cambridge-10.1557/JMR.1998.0268 Early age microstructure of the paste-aggregate interface and its evolution [Elektronische Daten] The sequence of microstructural changes occurring at the wet paste-aggregate interface is documented at an age as early as 5 min using the environmental scanning electron microscope (ESEM). Unlike other microscopic techniques, the ESEM allows pastes of normal water: cement ratio to be observed at early ages without reducing the paste to a powder. Evolution of the paste-aggregate microstructure is followed up to an age of 24 h. The region adjacent to the aggregate surface contains a phase with a morphology referred to as a "sheaf of wheat” morphology. The same interfacial region in a 10-day-old specimen has a microstructure similar to the interfacial transition zone (ITZ) reported in the literature. Variations of the "sheaf of wheat” morphology due to original water-to-cement ratio, mixing energy, incorporation of silica fume, and drying are documented. As revealed by energy dispersive x-ray analysis (EDS), the microstructure contains significant amounts of calcium and silica. These results indicate that the observed morphology is likely to be a calcium silicate hydrate (C-S-H) product that is a precursor to type I C-S-H. A description of the evolution of the observed microstructural features is presented. The "sheaf of wheat” morphology appears to be a general precursor to morphologies commonly seen in mature pastes. Copyright © Materials Research Society 1998 Zampini Davide Department of Civil Engineering, NSF Center for Advanced Cement-Based Materials, Northwestern University, Evanston, Illinois 60208 Shah Surendra P. Department of Civil Engineering, NSF Center for Advanced Cement-Based Materials, Northwestern University, Evanston, Illinois 60208 Jennings Hamlin M. Department of Civil Engineering and Department of Materials Science and Engineering, NSF Center for Advanced Cement-Based Materials, Northwestern University, Evanston, Illinois 60208 Journal of Materials Research Cambridge University Press 13/7(1998-07), 1888-1898 0884-2914 13:7<1888 1998 13 JMR https://doi.org/10.1557/JMR.1998.0268 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1557/JMR.1998.0268 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zampini Davide Department of Civil Engineering, NSF Center for Advanced Cement-Based Materials, Northwestern University, Evanston, Illinois 60208 NATIONALLICENCE 700 1- Shah Surendra P. Department of Civil Engineering, NSF Center for Advanced Cement-Based Materials, Northwestern University, Evanston, Illinois 60208 NATIONALLICENCE 700 1- Jennings Hamlin M. Department of Civil Engineering and Department of Materials Science and Engineering, NSF Center for Advanced Cement-Based Materials, Northwestern University, Evanston, Illinois 60208 NATIONALLICENCE 773 0- Journal of Materials Research Cambridge University Press 13/7(1998-07), 1888-1898 0884-2914 13:7<1888 1998 13 JMR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge